Enumerating subgraphs of a given graph is a fundamental task in computer science. Since the number of subgraphs can be exponentially larger than the input graph size, it is not practical to list all subgraphs one by one. To overcome the difficulty, we focus on implicit enumeration algorithms. Such an algorithm constructs a decision diagram (DD) representing the set of subgraphs instead of explicitly enumerating the subgraphs. In this talk, we introduce recent studies on implicit subgraph enumeration using DDs.